COLUMBIA, Mo. – University of Missouri Extension specialists are urging Missouri growers to scout corn crops for corn leafhopper.
It was first confirmed in southwestern Missouri in Christian County in 2024 and in Lawrence and Boone counties on the week of July 7, 2025, says MU Extension state crops entomologist Ivair Valmorbida.
The reports that corn leafhopper has been found in four states. It also is prevalent in South America and Mexico.
Following last year’s detection in Missouri, growers, crop consultants and industry partners urged farmers to be on the lookout for the pest.
The small, pale yellow to greenish yellow insect feeds on corn and its wild relatives. It carries pathogens that cause corn stunt disease. This leads to deformed grain, loose kernels and short stalks. If populations are high, corn leafhoppers can also reduce yields due to feeding on the phloem.
Corn stunt symptoms generally appear within 30 days of infection. By then, there is nothing farmers can do, Valmorbida says.
The invasive insect threatens corn production in two ways: through direct feeding on corn plants and by transmitting four pathogens associated with corn stunt disease.
Corn leafhoppers reproduce only on corn and its relatives. They overwinter in southern states but not in Missouri due to its cold winters.
Corn leafhoppers is sometimes confused with other pests, including the aster leafhopper. “Accurate insect identification is essential for effective pest management,” says Valmorbida.
The insects are hard to spot because they are only 1/8 inch long. One indicator of infestation is shiny leaves due to honeydew excretions left after feeding. The honeydew can lead to a black, sooty mold that affects photosynthesis and plant health.
They move rapidly within and among cornfields and fly or jump away when disturbed. They can be found in shaded areas of corn, resting and feeding in the whorl of young plants and hidden on the undersides of leaves.
Corn stunt symptoms show as chlorosis and/or reddening of leaf tips. After that, the shorter corn plant produces auxiliary buds and multiple ears with loose or missing kernels.
Valmorbida recommends using yellow stick cards, sweep nets and visual inspections for scouting cornfields.
Management strategies must focus on the insect, he says. Currently, there is no economic threshold for this pest. Valmorbida’s recommendations are to reduce the chances of infestation.
- Plant as early as possible to reduce the chances of infestation by corn leafhoppers.
- Insecticidal seed treatments can provide control of corn leafhoppers only up to the V3 growth stage.
- Consider foliar insecticides if corn leafhoppers are present before the reproductive growth stages.
Learn more from MU Extension publication G7109, , which is available for free download.
You can sign up for pest alerts for your area through .
The Crop Protection Network has a in the U.S.
If you suspect its presence in your crops, collect the insects and submit them to the .
MU Plant Diagnostic Center: https://extension.missouri.edu/programs/plant-diagnostic-clinic